Role of Multi-Slice Computed Tomography in Assessment of Non-Cyanotic Congenital Heart Disease

Abstract

Congenital heart defects (CHD) are the most frequent group of congenital abnormalities. Notwithstanding of considerable improvement in medical and surgical management of new-borns with CHD, there is significant mortality and morbidity associated with CHD, which comprise the first cause of mortality by congenital anomalies. Furthermore, survivors may have sizeable short-term morbidity and long-term adverse neuro-developmental outcomes. Acyanotic congenital heart disease (ventricular septal defects “most common”, patent ductus arteriousus, atrial septal defect and pulmonic stenosis and coarctation of aorta) represent 70% of all congenital heart disease. Transthoracic echocardiography (TTE) is the first imaging modality in congenital heart disease; it offers full intra-cardiac anatomic and hemodynamic details. But, it diagnostic role is limited by poor echo windows in older children and in postoperative cases by scars, chest wall deformities, lung artefact. Invasive cardiac catheterization has been, for long time, the gold standard for the anatomical assessment of CHD in children, having the potential to anatomical and hemodynamic evaluation. But on the other hand its has disadvantages (vessel dissection, stroke, pseudo aneurysm formation, costs of hospital stay, patient discomfort, radiation dose, and contrast medium). Moreover, cardiac catheterization is not informative regarding associated airway pathology. MRI has been recently suggested to explore cardiac anatomy. The lack of radiation dose is a great advantage compared to conventional angiography or MSCT. However, MRI in small children often needs anesthesia with dose monitoring. Moreover, Image quality with MR is lower than image quality with MSCT due to lower MR spatial resolution. Assessment of simple defects, for example atrial septal defect (ASD) and ventricular septal defect (VSD), can be usually done with echocardiography, additional imaging studies, such as computed tomography (CT), magnetic resonance imaging (MRI), and cardiac catheterization, are often required for the accurate diagnosis and optimal treatment of more complex defects. Among those additional imaging modalities, the role of MSCT has greatly increased, thanks to recent technical evolutions Non-ECG-synchronized spiral scanning is better to assess extra-cardiac vascular (PDA, Pulmonary stenosis, coarctation of Aorta, and Aorto-pulmonary window) and airway abnormalities of paediatric CHD. ECG-synchronized scanning with either retrospective ECG gating or prospective ECG triggering should be performed for the evaluation of intra-cardiac structures (VSD, ASD, AVSD, PFO and cardiac valves). Multi-planar and 3D CT reconstruction images can improve communication of anatomic details to clinicians. MSCT has demonstrated to be a priceless diagnostic and decision-making tool. The feasibility and efficiency of low dose MSCT angiography as a non-invasive technique in distinguishing anatomic structures of CoA without any significant loss of diagnostic data. MSCT with three-dimensional reconstruc-tion displayed the vascular structures clearly; thus, it can be used in place of conventional angiography in the diagnosis and follow-up of patients with CoA. Radiation exposure is vital in the paediatric population because children are considered to be more sensitive to ionizing radiation than adults, and they have a longer life expectancy. The main drawback of MSCT is radiation exposure. Computed tomography protocols are associated with a known increase in the risk of future malignancy. According to these findings, dose-saving algorithms are very important in reducing radiation exposure and should be used in every imaging modality, especially during infancy and childhood.